An electric automobile is a vehicle using batteries as power source. Since the electric automobile has a smaller adverse effect on the environment than traditional automobiles, the electric automobile is the development trend of future automobiles as the requirements for energy conservation and emission reduction for automobiles continuously increases.
The batteries of the electric automobile generate heat during operation, which increases the temperature of the batteries, and the longer the batteries operate, and the more heat the batteries accumulate, thus the temperature of the batteries gets higher. If the batteries are not cooled in time, the working performance and service life of batteries will be adversely influenced. In the conventional technology, batteries of the electric automobile are generally cooled by a battery cooling system, the cooling capacity of which is generally provided by an air conditioning system of the electric automobile.
In general, the battery cooling system includes a plate heat exchanger and a thermal expansion valve. The plate heat exchanger substantially has two kinds of structures, one kind is formed by stacking a series of heat exchanging plates with certain corrugations, and the other kind employs fin structures between heat exchanging plates as flow passages. Both structures may form a passage for an interaction between the two kinds of media to realize heat exchange between the two kinds of media. When the plate heat exchanger is applied in the battery cooling system, two kinds of media in the passage are a refrigerant and a cooling liquid. The principle of the battery cooling system is described as follows, after flowing out of a thermal expansion valve, the refrigerant cools the cooling liquid via the plate heat exchanger, and then the cooling liquid cools the batteries via a battery cooling plate.
Reference is made to FIG. 1. The connection between a conventional plate heat exchanger 1′ and a thermal expansion valve 2′ is realized by leading out connecting pipes 3′ at a refrigerant inlet and a refrigerant outlet of the plate heat exchanger 1′ to connect to the thermal expansion valve 2′. However, this indirect connection has the following disadvantages.
1. Since the plate heat exchanger 1′ and the thermal expansion valve 2′ has a complicated connection structure, the assembly has a large volume, and is inconvenient to be installed inside the automobile.
2. The plate heat exchanger 1′ and the thermal expansion valve 2′ are connected by pipelines, thus there are many parts, and the cost is relatively high.
3. Connection pipelines between the plate heat exchanger 1′ and the thermal expansion valve 2′ are long, thus the whole assembly has a poor vibration-proof performance, and ruptures of the connection pipe and other phenomena are apt to occur.
4. As pipelines and other materials are added, the whole assembly has a heavy weight.
5. The refrigerant needs to pass through the pipelines to flow from the thermal expansion valve to the plate heat exchanger, which is bound to adversely affect the refrigeration effect.
Therefore, an urgent technical issue to be addressed by the person skilled in the art is to integrate a heat exchanger with other parts, to enable the heat exchanger to be directly connected to the expansion valve, so as to enable the heat exchanger to have a compact structure, a good vibration-proof performance, a low cost and be easy to install.